The most popular and best-controlled way of roasting coffee is semi-hot air baking Italian blend of coffee beans.

Semi-hot air baking

This is currently the most popular and best-controlled way of roasting coffee. It can make up for the shortcomings of the direct-fire roaster, improve safety, and show the aroma and flavor of coffee.

Many people say, "with the change of season or weather, the results of baking will vary a little." This sentence does not seem to be suitable for semi-hot air baking. Because the semi-hot air roaster is not as easily affected by the external environment as direct fire. So the use of good quality raw beans, coupled with the same benchmark operation, the baked beans flavor and aroma will be exactly the same, in the quality control will not cause too much problem.

Advantages:

The temperature inside the boiler is easy to adjust: the firepower of the semi-hot air roaster is relatively stable, so it is not affected by the external environment. As long as you adjust the heat, you can easily control the firepower needed for each baking stage. However, after the explosion of the beans, the treatment method of the roaster is different from that of the direct fire roaster. After the explosion, the firepower should be concentrated on the inside of the boiler, and even if the firepower is reduced, the temperature should not be allowed to drop, so as to prepare for the sufficient energy needed for the expansion of raw beans. Therefore, it is necessary to pay attention to whether the temperature in the furnace drops after the explosion. If the firepower is not enough, it is necessary to add 1 ~ 2 grids of firepower.

Stable supply of firepower to help raw beans expand evenly: the characteristic of semi-hot air type is that the internal and external tissues of raw beans can be heated evenly and the firepower is stable. Thus, the flavor and aroma of coffee beans are relatively stable. Compared with the beans baked by the direct-fired baking machine, the beans blown out by semi-hot air are lighter in color at the same baking degree.

Suitable for roasting of blended coffee: if beans of different densities are mixed, the semi-hot air machine is more stable because the heat energy conveyed is more uniform. The heat provided by the semi-hot air reaches the central part of the bean, so even if the density of the raw bean is different, the heat source provided by the baking machine can be completely absorbed by the raw bean.

Single mixed beans: (Blending After Roasting) baked individually and then blended

Mixed beans: (Blending Before Roasting) mix the beans before baking.

Disadvantages:

Sufficient preheating time is needed: compared with direct fire, a semi-hot air bean dryer takes at least 30 minutes to preheat. In case of insufficient preheating and baking, the tissue of the beans cannot expand evenly, resulting in inconsistent color of the coffee beans, not to mention the stability of the flavor and aroma of the coffee beans.

The initial firepower setting is important: in the first endothermic reaction, the firepower is too strong compared to the amount of raw beans, resulting in the first burst earlier. If the endothermic reaction has already begun, it will be difficult to adjust the firepower. As a result, the first explosion and the second explosion point are too close to distinguish. Most of the baked beans are mixed with grass flavor and raw bean flavor, which is due to the fact that the beans are not cooked at all.